Improvement in compensating spring-balances for safety-valves



V. F. LASSUE.

Compensating Spring-Balances for Safety-Valves. N0. 42,481. PatentedSeptember2,1873.

1 5 q a v l l l l UN'IE STATES A'IENT VALDEMAR F. LASSOE, OFBROOKLYN,ASSIGNOR TO VALDEMAR FREDRIK LASSOE AND GEORGE FREDRIGK MEYER, OF NEWYORK, N. Y.

IMPROVEMENT IN COMPENSATING SPRING-BALANCES FOR SAFETY-VALVES.

Specification forming part of Letters Patent No. 142,481, datedSeptember 2, 1873; application filul June 5, 1873.

To all whom it may concern:

Be it known that I, VALDEMAR FREDRIK LASSOE, of Brooklyn, in' the countyof Kings and State of New York, have invented an Improved CompensatingSpring-Balance for Safety-Valves, of which the following is aspecjfication:

Figure 1 is a side view of the improved compensating spring-balance forsafetyvalves; Fig. 2, a horizontal section on the line 0 0, Fig. 1.

This inventionhas for its object to provide a spring-balance forsafety-valves, with means for adjusting and regulating the power of thespring, so that such power will not be increased with the opening of thevalve.

On locomotives, 'steamships, &c., where the application of a weight tothe safety-valve is not practicable, owing to the jarring motion of theengine or the rolling of the vessel, and the consequent injurious effectwhich the weighted lever would exert upon the valve, springs have beenintroduced in place of the weights. These spring-balances were, however,very defective in one particularthat is, as the valve was raised oif itsseat by pressure of steam the spring, being thereby affected, increasedits resistance to the action of the steam upon the valve, and thereforeit required a greater steampressure to keep the valve open than it didto open the same; consequently the increased power of thespringsufticed, immediately after the opening of the valve, to reclosethe latter, and thus the chief object of a safety-valve was defeated.Various attempts have been made to counteract this injurious effect ofthe increase of the spring-power, but none that were successful.

The present invention aims at such a compensation of the spring-balancethat the power of the spring will remain nearly the same, or perhapseven become decreased, as the valve is being lifted olf its seat. Thisobject is partly attained by connecting the off end of thespring-balance with a vibrating bell-crank lever or quadrant, in suchmanner that the distance between the valve-lever and the point ofconnection of the spring with the aforementioned quadrant-lever will beless increased during the upward motion of the valve-lever than if thespring were secured to a stationary point, owing to the consequentvibration of the quadrant toward the valve-lever. It is evident thatthis circumstance will only partly contribute to compensate theincreased force of the spring, because the latter surely elongates. Tomake up for the balance, the valvelever and quadrant or bell-crank areconnected by a link, which transmits back to the former a fraction ofthe strain exerted upon the spring by the pressure of the valve, thusleaving the difl'erence of these two items as effectual resistance tothe steam-pressure. 1f, forexample, the safety-valve is set to obey asteampressure of thirty pounds, and the spring properly adjusted torepresent such power of thirty pounds, the effect of an excess ofsteam-pressure will be the elevation of the valve; but upon itselevation, and consequent transmission of motion to the spring-balance,the latter will still retain its resisting power of thirty pounds, andwill, with the use of thisinvention, not increase in power, therebyallowing the steam, as long as there is an excess of pressure, to keepthe safety-valve open. The adjustment of the parts may be such that thespring-pressure may be brought down, say, to twenty-nine pounds,perhaps, when the valve is raised to facilitate the keeping open of thevalve by the least excess of steam-pressure. The lever, quadrant, orbell-crank is slotted or perforated, or otherwise so arranged as topermit the point of its connection with the spring-balance, and alsowith the connectinglink, to bevaried at pleasure, sothat the rap paratuscan be set at any suitable decrease of steam-pressure. This adjustmentcan also be effected by moving the fulcrum or supportingbracket of thequadrant to and fro in a line parallel to the valve-lever; and thearrangement will yield the same result it the quadrant is turned so thatthe spring-connection will come between the link and valve, instead ofhaving the link placed between the valve and the spring.

In the accompanying drawing, the letter A represents a safety-valve ofsuitable construction, placed upon an appropriate seat, B, of

the steam-dome C, or other part of a boiler. The valve A is, by a link,a, connected in the ordinary or suitable manner with a beam or lever, D,which is, at b, pivoted to a fixed post or standard, (1. The outer endof the leverD is connected with a spring-balance, E, the latter being ofthe customary construction-that is to say, one end of the springcontained in such balance is connected with the rod 0 that is secured inthe beam D, while the other end of such spring is connected with thelower end of the balance, so that the more the end f is drawn away fromD the more will the power of the spring within E be increased. The lowerend f of the spring-balance is, by a rod, 9, connected with alever-quadrant or bellcrank, F. that is, at h, pivoted to a fixed frameor standard, G. The pin 1', which connects the rod 9 with the quadrantF, is beneath the pivot of F, as shown. A link, H, connects the beam Dwith the upper part of the quadrant F, as shown. In the drawing, thevalve A is represented as being closed upon its seat. l/Vhenever, by anexcess of steam-pressure within the dome or boiler O, the valve israised ofi" its seat, the beam D will be swung up, in the direction ofthe arrow Z, on its pivot 12. By such motion of the beam, and theconnection of the same with the quadrant, the latter will be caused toswing on its pivot h in the direction of the arrow m. By such movementof the quadrant the connecting-point i of the spring-balance with thequadrant will be elevated, and, therefore, the extension of the springwith E, and its consequent increase of power, will be less than it wouldhe were the lower part of the spring-balance E fixed instead of movable.In consequence of the motion of the quadrant F a back pressure isexerted by the link H upon the lever D, which pressure increases as therod 9 moves away from the fulcrum h. Hence, the more the valve is liftedoft its seat the more effectual will be the action of the link H. Thisis a very important point of the construction. By adopting suitablerelations between all the dimensions the efiect of the spring on thevalve may be kept nearly uniform, or may even be made to decrease whilethe valve'is raised.

For permitting the proper adjustment of the parts the quadrant F may beperforated, as shown; or it may be slotted or otherwise constructed toallow the pins 13 and n to be set in the desired manner, for it isevident that the further down the pin 5 is originally set on the leveror bell-crank F the larger will be its proportion of motion during theraising of the valve, and the larger, therefore, the counteractinginfluence of such motion upon the increased spring-power. It is alsoevident that the nearer the pin a is set to the pivot h the greater willbe the power exerted by the linkconnection H upon the lever D. The upperpivot 0 of the link H may also be adjustable upon the beam D, byperforating or slotting the latter, or otherwise, so that the power ofthe link-connection may be increased the further 0 is set away from I),and reduced the nearer 0 is set to b.

I desire it to be distinctly understood that I do not claim anyconnection of the balancespring E with a support which is rigidlysecured, as I know this to be an old and wellknown arrangement of parts,which, by my invention, I have attempted to improve.

I claim as my invention and desire to secure by Letters Patent- Thequadrant or bell-crank lever F, connected by a link, H, with the lever Dof a safety-valve, and combined with the springbalance E, which connectswith both levers D and F, substantially as and for the purpose hereinshown and described.

V. F. LASSOE. Witnesses:

A. V. BRIESEN, FRED. HAYNES.

